Engine fuel system or other fluid transfer systems



M. A. TRISLER March 8, 1949.

ENGINE FUEL SYSTEM OR OTHER FLUID TRANSFER SYSTEMS Filed Oct. 21, 1943 Patented Mar. 8, 1949 ENGINE FUEL SYSTEM R OTHER FLUID TRANSFER SYSTEMS Milton A. Trlsler, Indianapolis, Ind., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application October y21, 1943, Serial No. 507,096 19 Claims. (Cl. 123-119) This invention has to do with fluid transfer systems, more particularly uid transfer systems which oper-ate under varying conditions of ambient pressure. such as fuel systems for airplane internal combustion engines which operate under varying conditions of atmospheric pressure.

The principal object of the invention is to provide a fluid transfer system in which the effect of changes in the ambient pressure on the pressure and/or the rate of flow of the fluid in the system is minimized.

More specifically, the invention has to do with fluid transfer systems in which there is a member through which the pressure and/or rate of flow of the fluid in the system is affected by pressure external to the system and has for its object to provide means for minimizing the effect of variations in the ambient pressure on the, member and thus for minimizing the effect of variations in the ambient pressure on the pressure and/or rate of flow of fluid in the system.

The invention is particularly applicable to carbureting apparatus for engines of the class mentioned in which the fuel is injected into a stream of air'whose pressure is at times lower and at times higher than that of the atmosphere by a by-pass type fuel pump through a metering device and a nozzle which is opened by the pressure of the fuel.

In its application to carbureting apparatus of the type described, the principal object of the invention is to provide carbureting apparatus in which the pressure of the fuel at the nozzle is at all speeds of the engine under all conditions of atmospheric pressure maintained sufficiently high -and uniform to inject the fuel into the stream of air at the desired rate.

For a better understanding of the objects and nature of this invention reference is made to the following specification and the accompanying drawing wherein there is described and illustrated the preferred embodiment of the invention.

In the accompanying drawing:

Figure l is a more or less diagrammatic view of carbureting apparatus of the type described in which my invention is embodied installed on an internal combustion airplane engine.

Figure 2 is an enlarged view of the fuel pump included in the carbureting apparatus.

Figure 3 is an enlarged view of the fuel nozzle included in the carbureting apparatus.

In the drawing the reference character I0 indicates an internal combustion engine with a main centrifugal supercharger which includes an impeller II and an auxiliary centrifugal super- 2 charger which includes Aan impeller I2. The impeller Il of the main supercharger is driven from the crankshaft'of the engine at a speed proportionate to the speed of the engine through gearing which is indicated -generally by the reference character I3. The impeller I2 of the auxiliary supercharger is driven from the crankshaft of the engine at a speed which varies with respect to the speed of the engine through elements of thegearing I3, a gear Il, gearing I5, a universal joint I6, a fluid coupling I1 and gearing I8.

From a point at which air is forced into it by movement of the airplane to the intake side of the auxiliary supercharger there extends a duct I9 to whose outer end there is connected a scoop 20 which faces in the direction of movement of the airplane. In the duct I8 between the scoop 20 and the auxiliary supercharger there is interposed a device 2i, such as is used in the Stromberg injection carburetor, which meters fuel at a rate which bears the desired relation to the rate of fiow of 4air through the duct. To regulate the rate of flow of air through the duct and, thus. the speed of the engine I0, there is incorporated in the fuel metering device a butterfly type throttle valve 49. From the discharge side of the auxiliary supercharger to the intake side of the main supercharger extends a duct 22 into which projects immediately in advance of the impeller II of the main supercharger a fuel nozzle 23 which is connected to the fuel metering de vice 2| by a tube 24.

To advance fuel to the metering device 2I and. thence, to the fuel nozzle 23 through the tube 2l there is provided a fuel pump 25. The fuel pump 25 includes a body 28 with a fuel intake opening connected to the fuel tank of the airplane by a pipe 21 and a fuel discharge opening connected to the metering device by a pipe 2B and an impeller 29 driven by the engine at a speed proportionate to the speed of the engine I0 to draw fuel into the intake opening and discharge it from the discharge opening. In the body 26 of the fuel pump there is provided a by-pass 30 through which fuel may return from the discharge opening to the intake opening -and in this by-pass a valve 3|. The valve 3l is urged to position to close the by-pass by a spring 32 and connected to a flexible diaphragm 33 whose inner side is exposed to the pressure of the fuel in the bypass so that the valve will open when and remain open as long as the pressure of the fuel at the discharge opening of the pump exceeds the pressure to which the outer side of the diaphragm 3 is exposed by a se1ected amount to the end of maintaining constant the pressure at which fuel is discharged from the pump.

To regulate the discharge- 'of fuel from the nozzle 23Y there is provided within the nozzle a conical valve 34 with a stem 35 which is urged by a spring 35 to the position in which it closes the discharge orifice 31 in the nozzle and connected to a. exible diaphragm 38 whose inner side is exposed to the pressure-of the fuel inthe nozzle so that the valve will open and fuel will be injected into the duct 22 when the pressure of the fuel in the nozzle exceeds the pressure to which the outer side of thel diaphragm is exposed by a certain amount and the valve will remain open and fuel will continue to be injected into the duct 22 as long as the difference in pressures exceeds this amount. When the engine I is operating, air enters the scoop 20 and passes therefrom through the duct I9, the metering device 2l and the auxiliary supercharger into the duct 22. Fuel is injected through the nozzle 23 into the air in the duct 22 and with it ipasses through the main superfcharger into the cylinders of the engine.

To insure injection of fuel into the duct 22 in the form of a spray which will readily be entrained by the air in the duct, it is, Vof course,

necessary to maintain the pressure of the fuel the fuel nozzle 23 at a valve well above that of the air in the duct 22 and 'the effective area of the orice 31 in the fuel nozzle below a value which varies with the rate at which fuel is delivered to the fuel nozzle. To insure these things, it is necessary that the pressure at which fuel is discharged from the fuel pump 25 be maintained above a certain value and the valve 34 in the fuel nozzle be prevented from opening too far. To do these things it is necessary to prevent the pressure on the outer sides of the diaphragms 33 and 38 of the fuel pump and the fuel nozzle fall- 33. The interiors of these covers are connected to the interiors vof the scoop 20 and the duct 22 through a valve so constructed that the higher 'of the pressures of` the air in the scoop and the air in the duct 22 is applied-to the outer sides of the diaphragms 33 and l38. 'Ihe valve referred to is indicated in the drawing by the reference character 4I. It includesa hollow body which consists of dished members 42'and 58 between whose margins and between bars5| and 52 which extend across the dished members near one side is clamped a flexible diaphragm 43 with an aperture 53 in it between the margins of the dished members and the bars. The connections between the interiors of the covers 39 and 40 and the interiors ofthe scoop 2B and the duct 22 which were mentioned are afforded by pipes 44, 45, 4,6, 4l' and ing below a selected value and to-insure injection of fuel into the duct 22 at a rate which bears the desired relation to the rate of ow of air to the engine and in the most desirable form it is preferable to maintain the pressure on the outer sides of the diaphragms constant.

Through the fluid coupling I l the rate at which the impeller I2 of the auxiliary supercharger is driven is so regulated that the pressure in the duct 22 is maintained at about that ofthe atmosphere at sea level under all conditions of atmospheric pressure which obtain up to a selected altitude except whenthe engine is operating at low speeds when it is impracticable so to regulate it. At altitudes greater than the selected altitude the'range within which the engine l is intended to operate the rate at which the impeller of the auxiliary supercharger is driven is, through the fluid coupling, so regulated that the pressure in the duct 22 is, except, of course, when the engine is operating at low speeds, maintained at a value which while lower than that at which it is maintained up to the selected altitude is still higher than that of the surrounding atmosphere. The pressure in the duct 22 is, consequently, at times higher and Vat times lower than the pressure of the surrounding atmosphere.

To maintain the pressure on the outer sides of the diaphragms 33 and 38 of the fuel pump and fuel nozzle as nearly constant as possiblerat all speeds of the engine I0 under all conditions of atmospheric pressure, there is provided on the fuel pump a cover 39 for the diaphragm 33 and on the fuel nozzle a cover 40 for the diaphragm 48. The pipes 44 and'45 are connected, respectively, to the interior of the cover 33 and the interior'of the cover 40. The pipe 46 is connected to the pipes 44 and 45 and to the interior of the body of the valve 4I near the aperture 53 in the flexible diaphragm 43 so that it communicates with it on both sides of the diaphragm. The pipe 41 is connected to the interior-of the scoop and to the interior ofthe body of the valve 4| on one side and the pipe 48 is connected'to the interior of the duct 22 and to the interior of the body of the valve 4I on the other side of the imperforate portion of the diaphragm 43.

This arrangement insures that the outer sides of the diaphragms 33 and 38 will always be subjected to the higher of the pressures of the air in the scoop 26 and ofthe air in the duct 22 and, consequently, that the pressure on the outer sides of the diaphragms will be maintained as nearly constant as possible at all speeds of the engine under all conditions of atmospheric pressure. If the pressure of the air in the scoop becomes higher than the pressure of the air in the duct 22, the diaphragm 43 will op over to a position in which it blocks communication between the duct 22 and the interior of the body of the valve and, consequently, as long as this condition obtains the outer sides ofthe diaphragms 33 and 38 will be subjected to the pressure of the air in the scoop. If the pressure of the air in the duct 22 becomes higher than the pressure of the air in the scoop, the diaphragm will flop over to a position in which it blocks communication between the scoop and the interior of the body of the valve and; consequently, as long as this condition obtains the outer sides of the diaphragms 33 and 38 will be subjected to the pressure of the air in the duct 22. The condition first mentioned obtains, as I have indicated, only when the engine is operating at low speeds. t

The arrangement which has been disclosed is not limited to use in conjunction with the particular carbureting apparatus which has been illustrated and described.- It can also be used in conjunction. with carbureting apparatus which includes one or more superchargers on whose engine side or sides thel fuel is injected. It can also be used in commotion with carbureting appa.-

ratus which includes one or more superchargers on whose atmospheric side or sides the fuel is injected but in the case of carbureting apparatus of this type it is not so important to apply the larrangement to the fuel nozzle. In the case of carbureting apparatus which includes a fuel pump of other than the by-pass type the arrangement may be applied to the fuel nozzle only.

Although I have illustrated and described my invention applied in a particular manner to a.

particular type of fuel supply system for a particular type of internal combustion airplane engine carbureting apparatus and lhave pointed out that it may be applied to other types of fuel supply systems for other types of carbureting apparatus, it is to be understood that the invention may also be applied to fluid transfer systems other than fuel supply systems for carbureting apparatus.

I claim:

1. In carbureting apparatus for internal combustion engines, a duct, a pump driven at a speed which ls variable with respect to the speed of the engine for moving air through the duct toward the engine, a pump driven` at a speed proportionate to the speed of the engine for moving air from the duct on the engine side of the first specified pump toward the engine, means for metering. fuel in accordance with the flow of air through the duct interposed in the duct on the atmospheric side of the first specified pump, a pump with a by-pass through which fuel may return from the discharge side to the intake side of the impeller of the third specified pump for advancing fuel into the duct between the first specified pump and the second specified pump, a

valve movable toward and away from a positionl in which it obstructs the passage of fuel through the by-pass, means through which the pressure of fluid external to the third specified pump-urges the valve toward the position in which it obstructs the passage of fuel through the by-pass, means, including an orifice, through which fuel is introduced into the duct between the first specified pump and the second specified pump, a valve which is movable toward and away from a"posi tion in which it obstructs passage of fuel through the orifice, means through which the pressure of the fuel advanced by the third specified pump urges the second specified valve away from and the pressure of fluid external to the second specified valve moves the second specified valve toward the position in which it obstructs passage of fuel through the orifice, and' means for transmitting to the second and fourth specified means the higher of the pressure of the atmosphere and the pressure of the fluid in the duct between the first specified pump and the second specified pump, including a valve which communicates with the atmosphere and with the duct between the first specified pump and the second specified pump and includes a member movable by the difference between the last mentioned pressures to a position in which it blocks communication between `the atmosphere or the duct and the third specified valve.

2. In carbureting apparatus for internal combustion engines, a duct, a pump for moving air through the duet toward the engine, a pump with a by-pass through which fuel may return from the discharge side to the intake side of the impeller of the second specified pump for advancing fuel into the duct` a valve which lsmovab1e toward and away from a position in which it obstructs the passage of fuel through the by-pass, means through which the pressure of fluid external to the second specified pump urges the valve toward the position in which it obstructs the passage of fuel through the by-pass, means,

including an orifice, through which fuel is advanced by the second specified pump to the duct, a valve which is movable toward and away from a position in which it obstructs the passage of fuel through the orifice, means through vwhich the pressure of the fuel advanced by the second specified pump urges the second specified valve away from and the pressure of fluid external to the second specified valve moves the second specifled valve toward the position in which it obstructs passage of fuel through the orifice, and means for transmitting to the first and third specified means the pressure of the fluid inthe duct on A the engine side of the first specified pump.

3. In carbureting apparatus for internal combustion engines, a duct, a pump for moving air through the duct toward the engine, a pump with a by-pass through which fuel may return from the discharge to the intake side of the impeller of the second specified pump for advancing fuel to the engine, a valve which is movable toward and away from a position in which it obstructs the passage of fuel through the by-pass, means through which the pressure of fluid external to the second specified pump urges the valve toward the position in which it obstructs the passage oi' fuel through the by-pass, means, including an orifice, through which fuel is advanced by the pump to the engine, a valve which is movable toward and away from a` position in which lt obstructs the passage of fuel through the orifice, means through which the pressure of the fuel advanced by the second specified pump urges the second specified valve away from and the pressure oi' fluid external to the second specified valve moves the second specified valve toward the position in which it obstructs passage of fuel through the orifice, and means for transmitting to the first and third specified means the higher of the pressure of the atmosphere and the pressure of the P fluid in the duct on the engine side of the first specified pump.

4. In carbureting apparatus for internal combustion engines. a duct, a pump for moving air through the duct toward the engine, apump with a by-pass through which fuel may return from the discharge to the intake side of the impeller oi' the second specified pump for advancing fuel to the engine, a valve which is movable toward and away from a position in which lt obstucts the passage of fuel through the by-pass, means through which the pressure of fluid external to the second specified pump urges the valve toward the position in which it obstructs the passage of fuel through the by-pass, means, including an orifice, through which fuel is advanced by the pump to the engine, a valve which is movable toward and away from a position in which it obstructs the passage of fuel through the orifice. means through which the pressure of the fuel advanced by the second specified pump urges the second specified valve away from and the pres`= sure of fluid external of the second specified valve moves the second specified valve toward the posi# tion in which it obstructs passage of fuel through the orifice, and means for transmitting to the first and third specified means the pressure of the fluid in the duct on the engine side of the first specified pump.

5. In carbureting apparatus for internal combustion engines. a duct, a pump driven at a speed which is variable with respect to the speed of the engine for moving air throughA the duct toward the engine, a pump driven at a lspeed proportionate to the speed of the engine for moving air from the duct on the engine side of the first specified pump toward the engine, means for metering fuel in accordance with the flow of air through the duet interposed inthe duct on the atmospheric side of the first specified pump, means, including an orifice, through which fuel is introduced into the duct between the specined pumps, a pump for advancing fuel through the pressure of the atmosphere and the pressure of the fluid in the duct between the first specified pump and the secondspecied pump, including a valve which communicates with the atmosphere and with the duct between the first specified pump andthe second specied pump and includes a member movable by the difference between the pressures t0 a position in which it blocks communication between the atmosphere or the duct and the second specined valve. Y

6. In carbureting apparatus for internal combustion engines, a duct, a pump for moving air through the duct toward the engine, means, including an orifice, through which fuel is introduced into the duct, a pump for advancing fuel into the duct through the specied means, a valve which is movable toward and away from a position in which it obstructs passage of fuel through the orifice, means through which the pressure of the fuel advanced by the second specified pump urges the valve away from and the pressure of uid external to the valve moves the valve toward the position in which it obstructs passage of fuel through the orice, and means for transmitting to the second specified means the pressure of the uid in the duct on the engine side of the first specied pump.

7. In carbureting apparatus for internal combustion engines, a duct, a pump for moving -'air through the duct toward the engine, a pump for advancing fuel to the engine, means through which fuel is advanced by the pump to the engine including an orice, a valve which is movable toward and away from a position in which it obstructs the passage of fuel through the orince, means through which the pressure of the fuel advanced by the second specified .pump urges the valve away from and the pressure of fluid external to the valve moves/the valve toward the position in which it obstructs passage of fuel through the orifice, and means for transmitting to the second specified means thehigher of the pressure of the atmosphere and the pressure of the iiuid in the duct on the engine side of the ilrst specified pump.

8. In carbureting apparatus for internal combustion engines, a duct, apump for moving air through the duct toward the engine, a pump for advancing fuel to the engine, means through which fuel is advanced b y the pump to the en-v 8 9. In cerbureting apparatus for internal combustion engines. a duct, a pump driven at a speed which is variable with respect to the speed of the engine for moving air through the duct toward the engine, a pump driven at a speed proportionate to the speed of the engine for moving air from the duct on the engine side of the rst specied pump toward the engine, means for metering fuel in accordance with the flow of air through the duct interposed in the duct on the atmospheric side of the first specified pump, means through which fuel is introduced into the duct between the specied pumps, a pump with a bypass through which fuelmay return from the discharge ,side to the intake side of the impeller of the third specied pump for advancing fuel through the "iirst specified means and the second specified means into the duct, a valve which is movable toward and away from al position in which it obstructs the passage of vfuel through the by-pass, means through which the pressure of fluid external to the third specified pump urges the valve toward the position in which it obstructs the passage of fuel through the by-pass,

sition in which lt blocks communication between and means for transmitting to the third specified the atmosphere or the duct and the second spevcifled valve.

10. In carbureting apparatus for internal combustion engines, a duct, a pump for moving air through the duct toward the engine, means through which fuel is introduced into the duct, a pump with a by-pass through which fuel may return from the discharge side to the intake side of the impeller of the second specified pump for advancing fuel into the duct through the specied means by the pressure it applies to the fuel, a valve which is movable toward and away from a position in which it obstructs the passage of fuel through the by-pass, means through which the pressure of fluid external to the second specied pump urges the valve toward the position in which it obstructs the passage of fuel through the by-pass, and means for transmitting to the second specified means the pressure of the iiuid in the specified duct on the engine side of the first specied pump.

11. In carbureting apparatus for internal combustion engines, a duct, a pump for moving air through the duct toward the engine, a pump with a by-pass through which fuel may return from the discharge side to the intake side of the impeller of the second specified pump for supplying fuel to the engine, a valve which is movable toward and away from a position in which it obstructs the passage of fuel through the by-pass, meansY through which the pressure of iuid external to the second-specified pump urgesr the valve toward the position in which it obstructs the passage of fuel through the by-pass, andVv means for transmitting to the first specified means the higher of the pressure of the atmosphere and the pressure of the fluid in the duct on the engine side of the first specified pump.

l2. In carbureting apparatus for internal combustion engines, a duct, a pump for moving air through the duct toward the engine, a pump for casas advancing fuel to the engine, a valve whicnafl'ects the introduction of fuel into the engine, means through which the pressure of fiuid external to the valve alters the effect of the valve on the introduction of fuel into the engine, and means for transmitting to the first specified means the pressure of the atmosphere or the pressure of the fiuid in the duct on the engine side of the first specified pump.

13. In carbureting apparatus for internal com- -bustion engines. a duct, a pump for moving air through the duct toward the engine, a pump for advancing fuel to the engine, a valve which affects the introduction of fuel into the engine, means through which the pressure of fiuid external to the valve alters the effect of the valve on the introduction of fuel into the engine, and means for transmitting to the first specified means the pressure of fiuid at one point which is external to the valve or the pressure of fiuid at another point with respect to the valve which is external to the valve.

14. In an internal combustion engine which includes a duct and a pump for moving air through the duct toward the engine, fiuid transfer apparatus which includes a pump for advancing fluid with a by-pass through which the fiuid may return from the discharge to the intake side of the impeller of the second specified pumpI a valve which is movable toward and away from a position in which it obstructs the passage of the fiuid through the by-pass, means through which the pressure of fiuid external t the apparatus urges the valve toward the position in which it obstructs the passage of the fluid through the by-pass, means including an orifice through which the first mentioned fiuid is advanced by the second specified pump, a valve which is movable toward and away from a position inwhich it obstructs the passage of the first mentioned fluid through the orifice, means through which the pressure of the first mentioned fiuid urges the second specified valve away from and the pressure of fluid external to the apparatus moves the second specified valve toward the position in which it obstructs passage of the first mentioned fluid through the orifice, and means for transmitting to the first and third specified means the higher of the pressure of the atmosphere and the pressure of the air in the duct on the engine side of the first specified pump.

15. In an internal combustion engine which includes a duct and a pump for moving air through the duct toward the engine, fiuid transfer apparatus which includes a pump for advancing fluid with a by-pass through which the fiuid may return from the discharge to the intake side of the impeller of the second specified pump, a valve which is movable toward and away from a position in which it obstructs the passage of the fluid through the by-pass, means through which the pressure of fiuid external to the apparatus urges the valve toward the position in which it obstructs the passage of the fluid through the bypass, means including an orifice through which the first mentioned fiuid is advanced by the second specified pump, a valve which is movable toward and away from a position in which it obstructs the passage of the first mentioned fiuid through the orifice, means through which the pressure of the first mentioned fiuid urges the second specified valve away from and the pressure of fiuid external to the apparatus moves the second specified valve toward the position in which it obstructs passage of the first mentioned L. 10 K fiuid through the orifice. andmeans for transmitting to the first and third specified means the pressure of the air in the duct on the engine 'sid oi' the first specified pump.

16. In an internal combustion engine which includes a duct and a pump for moving air through the duct toward the engine, fiuid transfer apparatus which includes a pump for advancing fiuid, means including an orifice through which the fiuid is advanced by the pump, a valve which is movable toward and away from a position in which it obstructs the passage of the fiuid through the orifice, means through which the pressure of the fiuid urges the valve away from and the pressure of iiuidexternal to the apparatus moves the valve toward the position in which it obstructs passage of the first mentioned fluid through the orifice, and means for transmitting to the second specified means the higher of the pressure of the atmosphere and the pressure of the air in the duct on the engine side of the first specified pump.

17. In an internal combustion engine which inc ludes a duct and a pump for moving air through the duct toward the engine, fluid transfer apparatus which includes a pump for advancing fiuid with a by-pass through which fiuid may return from the discharge side to the intake side of the impeller of the second specified pump, a valve which is movable toward and away from a position in which it obstructs the passage of fluid through the bypassmeans through which the pressure of fiuid external to the apparatus urges the valve toward the position in which it obstructs the passage of fiuid through the by-pass, and means for transmitting to the first specified means the higher of the pressure of the atmosphere and the pressure of the air in the duct on the engine side of the first specified pump.

18. In an internal combustion engine which includes a duct and a pump for moving air through the duct toward the engine, fiuid transfer -apparatus which includes a pump for advancing fiuid, a valve which affects the advance of the fluid, means through which the pressure of fluid external to the apparatus alters the effect of the valve on the advance of the fiuid, and means for transmitting to the first specified means the pressure of the atmosphere or the pressure of the air in the duct on the engine side of the first specified pump.

19. In fiuid transfer apparatus, a pump for advancing fiuid, a valve which affects the advance of the fiuid, means through which the pressure of fluid external to the apparatus alters the effect of the valve on the advance of the first mentioned fluid, means for transmitting to the first specified means the pressure of fiuid at one point which is external to the apparatus or the pressure of fluid at another point with respect tothe apparatus which is external to the apparatus and at which the pressure of the fiuid varies with respect tc the pressure of the fiuid at said one point, and valve means controlled by the fluid pressures from the two points whenever one of the fluid pressures predominates over the other for selecting the predominant one to transmit solely the predominant pressure to the first Aspecified means by the second specified means.

MILTON A. sTRIsLER.

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